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TPS25923: Change ILIM setting when TPS259231 is already enabled

Antony Lin
Genius 13480 points
Part Number: TPS25923

Hi,

WHen TPS259231 is already enabled with 5V output, are we allow changing ILIM setting to change different current limit value?  We found the output 5V would drop at the moment when ILIM resistor value is changed.  Is it expected?

Thanks!

Antony

  • 0
    TI__Guru** 104006 points

    Hi Antony,

    You can change the current limit setting during operation but make sure the ILIM pin is not left OPEN during change.

    May I know how you are doing? from what value to what value.? what is the load current ?

    An example of doing dual current limit setting for another similar device is shown below.

    Best Regards,

    Rakesh

  • 0 in reply to Rakesh
    TI__Genius 13480 points

    Hi Rakesh,

    Thanks for your support.

    Customer uses schematics as below to change the ILIM value by controlling TYPEC_OUT_1-5A and TYPEC1_OUT_NEW signals.  The result is shown in the waveform plot as below.  What is your comment?

    Antony

    Antony

  • 0 in reply to Antony Lin
    TI__Guru** 104006 points
    Hi Antony,

    Thanks for the schematic and test waveforms.
    Can you please request waveforms of Output current, GATE voltage of Q22 during this transition.

    Regards
    Rakesh
  • 0 in reply to Rakesh
    TI__Genius 13480 points

    Hi Rakesh,

    Thanks!  Please see the waveform including BFET as below based on your request.  Since the customer can't find a scope current probe, they can only provide voltage/current reading before and after the ILIM transision in the bottom.

    Antony

    Antony

  • 0 in reply to Antony Lin
    TI__Guru** 104006 points
    Hi Antony,

    If the customer is using the Electronic load in CC mode, suggest them to use in CR mode. Can you ask them to test/check again.
    Looks like the device is going into thermal shutdown when switched from ILIM=HIGH to ILIM=LOW with the "same load impedance". Please refer the thread for more explanation and let me know if it is not clear.. e2e.ti.com/.../2210530

    Best Regards,
    Rakesh
  • 0 in reply to Rakesh
    TI__Guru** 104006 points

    Hi Antony,

    Did you able to get test waveforms in CR mode? and a zoomed waveform during ILIM setting change with 80ms timescale rather than 400ms. We cannot make out thermal shutdown response with too low timescale.

    Best Regards,
    Rakesh

  • 0 in reply to Rakesh
    TI__Genius 13480 points

    Hi Rakesh,

    After testing it with CR mode, customer can get expected behavior now.

    Thanks for your support!

    Antony